Miliaria (Heat Rash), A Simple Guide To The Condition, Diagnosis, Treatment And Related Conditions

his book describes Miliaria (Heat Rash), Diagnosis and Treatment and Related Diseases

The weather is hot and I have rashes on my skin.

These rashes are called heat rashes or miliaria.

Miliaria is a frequent skin disease produced by blockage and inflammation of eccrine sweat ducts.

Miliaria is often observed in:
1. Hot, humid or tropical climates,
2. Patients in hospital, and
3. The neonatal period.

Miliaria is also termed sweat rash or prickly heat rash.

Based on the level of the sweat duct obstruction, miliaria can be categorized into 3 subtypes:

1. Miliaria crystallina (sudamina), produced by obstruction of the sweat ducts close to the surface of the skin (epidermis);

2. Miliaria rubra, produced by obstruction of the sweat ducts deeper in the epidermis;

3. Miliaria profunda (tropical anhidrosis), produced by the sweat leaking into the middle layer of skin (dermis).

Miliaria, or eccrine miliaria, is an often observed skin disease activated by blocked eccrine sweat glands and ducts, inducing backflow of eccrine sweat into the dermis or epidermis.

This back flow produces a rash comprising sweat-filled vesicle formation under the skin.

The rash is normally self-limiting and recovers independent of treatment.

Miliaria crystallina is most often observed in neonates with the mean age of 1 week, affecting up to 9% of all neonates.

It can also happen in adults with fever.

Miliaria rubra is the most frequent form of miliaria.

It is observed in children and in up to 30% of adults who travel to a tropical environment or are unexpectedly exposed to heat and humidity.

Miliaria profunda is infrequent and manifests in adult males.

It is a complication of repeated incidents of miliaria rubra.

The main causes are:
1. Immature sweat ducts in a newborn child
2. A hot and humid environment
3. Intense physical activity
4. Fever
5. Occlusion of the skin with non-porous dressings or synthetic clothing against the skin
6. Prolonged bed rest.

Other diseases and treatments that have been linked with miliaria are:
1. Drug-induced hyperhidrosis
2. Adverse reaction to medication (isotretinoin, doxorubicin)
3. Stevens-Johnson syndrome/toxic epidermal necrolysis
4. Genetic disease (Morvan syndrome and pseudohypoaldosteronism type I)
5. Radiotherapy

Any hot or humid conditions and high fevers are linked with miliaria.

These have been identified as causes of miliaria:
1. Occlusion of the skin:
Transdermal drug patches and tight clothing have been linked with miliaria.

2. Type I pseudohypoaldosteronism:

Mineralocorticoid resistance causes loss of sodium through eccrine glands and has been linked with pustular miliaria rubra.

3. Strenuous physical activity:
Exercise increases the amount of sweating

4. Morvan syndrome:
A rare autosomal recessive disease that causes hyperhidrosis, is among other abnormalities, which are prone to miliaria.

5. Medicines:
Drugs that cause sweating such as bethanechol, clonidine, and neostigmine have been linked to miliaria.

Also, few cases of isotretinoin-induced miliaria have been documented.

Miliaria is diagnosed by its characteristic medical manifestation.

In serious cases or repeated episodes, a punch biopsy of the skin can be useful.

Miliaria is a medical diagnosis.

Laboratory tests are often not conclusive and not useful.

Since hot, sweaty situations are the main risk factors for miliaria, the general treatments to decrease sweating and eccrine duct blockage are necessary in the treatment of miliaria.

This involves:
1. Cooler environments,
2. Wearing breathable clothes,
3. Removing skin occluding objects such as band-aids or patc...